How Much to Reward Someone Who Returns Wallet?

How Much Would You Give Someone Who Returns Your Wallet?

A friend lost her wallet in the streets the other day, but thankfully, she was contacted by a good Samaritan who picked it up. Coming up with how much reward to give was new territory for her so she took a quick poll among our friends to see how much they would give. Many say that $20 is a good amount, but I'm wondering what you think the right amount is. How much would you reward someone who returns your wallet?